The present invention relates to imaging devices and, more particularly, to imaging devices capable of transmitting and receiving image data through a telephone line.
Recently, techniques of transmitting and receiving digital data through such transmission route as a telephone line are well known in the art. Also, it has been a recent trend for establishing techniques for transmitting and receiving photographic image data obtained with an electronic camera through such a telephone line. Such data communication is mostly realized by connecting a modem or like adaptor to the electronic camera and connecting the camera via the adaptor to the telephone line.
In the meantime, it has also been a recent trend for extensively using radio portable telephone sets such as so-called digital portable telephone sets (hereinafter referred to as PDCs) and PHSs. These telephone sets are all radio sets with their portability as a great feature. In view of recent electronic cameras which are mostly used as portable sets, the radio telephone lines constitute an optimum image data transmission route.
An example of the construction of a prior art image transmitting system for sending the data of an electronic camera to a radio portable telephone set will now be briefly described.
FIG. 7 shows such an image transmission system, in which a PDC 103 is connected via a PC card 102 to an electronic camera 101.
As shown in the Figure, the PC card 102 includes a communication interface 122, which is constructed as hardware and includes a digital error correction circuit 122a, high speed synchronous serials RX and TX, low speed asynchronous serials RX and TX, a function of processing transmission and reception signals and a predetermined interface (I/F). The PC card 102 also includes a CISC-CPU 121 for controlling the communication interface 122. The PC card 102 is connected by a PC card header 113 to the electronic camera 101, and it further includes a connector 123 to which the PDC 103 is connected.
The electronic camera 101 includes a RISC-CPU 111 having the role of controlling the entire system, and a connector interface 111 for connection to the PC card 102.
In the prior art image transmission system having the above construction, only a particular type of radio telephone set can be connected. Up to date, PDCs and PHSs are well known in the art as different types of radio telephone sets. These different types of telephone sets, however, can not be used commonly as digital data transmitting means. That is, the individual types of telephone sets are used with PC cards having different digital error correction circuits, and it is thus necessary to change the PC card to be used in dependence on the type of radio telephone set that is connected.
In the meantime, such a PC card can serve as an adaptor peculiar or exclusive to the connected telephone set, so that it may have a sole exclusive digital error correction circuit. The circuit is thus realized not as software but as hardware.
Concerning the electronic camera, a recently proposed one includes a communication interface having high speed synchronous serials RX and TX, low speed asynchronous serials RX and TX and a function of processing transmission and reception control signals.
FIG. 8 is a view showing an image transmission system using such an electronic camera, in which a PDC 203 is connected via a PC card 202 to the electronic camera 201.
As shown, the electronic camera 201 includes a communication interface 212 having high speed synchronous serials RX and TX, low speed synchronous serials RX and TX and a function of processing transmission and reception signals. The electronic camera 201 also includes an RISC-CPU 211 for controlling the communication interface 212.
The PC card 202 is connected by a PC card header 213 to the electronic camera 201, and includes a connector 224 to which the PDC 203 is connected. The PC card 202 further includes an interface 222 connected to the communication interface 212 of the electronic camera 201, a data processor IC 223 (i.e., digital error correction circuit constructed as hardware) for the PDC and CISC-CPU 221 for controlling the interface 222 and the IC 223.
Again in the image transmission system having the above construction, like the image transmission system as shown in FIG. 7, only a particular type of radio telephone set can be connected. That is, it is necessary to change the PC card to be used in dependence on the type of telephone set that is connected.
In the meantime, the PC card 202 can serve as an adaptor peculiar or exclusive to the type of the connected telephone set, so that it may have a sole exclusive digital error correction circuit. The circuit is thus realized not as software but as hardware.
While the image data transmitting and receiving system utilizing radio telephone line is convenient as described above, the PDC and the PHS are based on quite different data transmitting systems, and common property is lacking with respect to modems connected to the line. In addition, in view of the digital data transmitting system, the above radio telephone lines are different from the usual wired telephone line, and hence from modems connected thereto.
The electronic camera user thus has to prepare an adaptor corresponding to the type of telephone line (i.e., either wired or radio, or portable telephone set or PHS) that is utilized. Likewise, each communication carrier (i.e., PDC, PHS, etc.) requires an exclusive adopter (i.e, PC card). The PC card, although recently being on a reducing size trend, extremely spoils the portability of a portable camera when mounted on the body thereof. In addition, it is necessary to prepare an expensive exclusive PC card for each type of communication carrier, which is extremely uneconomical.